Changes in mannose-6-phosphate receptors and glycosidases induced by acrosomal reaction in bovine spermatozoa

AGUILERA AC; SARTOR T; CARVELLI L; SOSA MA; BOSCHÍN V; MICHAUT M

Mendoza

Congreso; XXXVI Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2018

Sociedad de Biología de Cuyo

Mammalian spermatozoa must undergo biochemical and morphological changes before the oocyte fertilization. Some of these changes are induced by capacitation and acrosomal reaction that occurs in the female genital tract. In previous studies we have described the presence of mannose-6-phosphate receptors (MPRs) on the bovine sperm (BS) surface and their interaction with glycosidases. The aim of this study was to analyse whether capacitation and/or acrosomal reaction may induce changes on these receptors and glycosidases. Epididymis from adult bulls (Aberdeen Angus) were carefully dissected and spermatozoa from cauda were collected by retro-perfusion. By flow cytometry, using specific antibodies, we observed that both MPRs, the cation-independent (CI-MPR) and the cation-dependent (CD-MPR) were detected in BS. After 2 hours of incubation in capacitation media (SP-TALP) and ulterior 20 min with the ionophore A23187, we observed that CI-MPR detection increases significantly due to capacitation. Meanwhile, the detection of both receptors increase significantly after acrosomal reaction. Some glycosidases, such as beta-N-acetyl-glucosaminidase can be partially removed from the sperm due to capacitation and acrosomal reaction, whereas alpha-fucosidase detection was increased after acrosomal reaction. No changes were observed for other glycosidases, such as beta-galactosidase, beta-glucosidase and alpha-mannosidase. These results suggest that MPRs and some glycosidases may be affected by the capacitation and acrosomal reaction in BS. These changes could provide new insights into molecular rearrangement that can take place before the fertilization of the oocyte.